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Air conditioning and heating systems are not only great for keeping a home cool or warm, but they also help clean the air of harmful pollutants.

While home thermostats control HVAC (heating, ventilation, and air conditioning) systems based on temperature, engineers from the University of Utah have studied the effects of controlling them based on a home’s indoor air quality. They have discovered that programming your air conditioner and furnace to turn on and off based on the indoor air quality as well as the temperature doesn’t waste a lot of additional energy but keeps the air much cleaner.

Their findings, published in a paper titled Smart Home Air Filtering System: A Randomized Controlled Trial for Performance Evaluation, were presented on Sept. 26 at this year’s “IEEE/ACM Conference on Connected Health: Applications, Systems and Engineering Technologies” in Washington D.C. The lead authors of the paper are University of Utah electrical and computer engineering professor Neal Patwari and U electrical and computer engineering doctoral graduate, Kyeong T. Min.

PHOTO CREDIT: University of Utah Professor Neal PatwariThis graph shows that when a home heating and air conditioning system turns on and off based on temperature alone (normal), the air quality in the home can result in the dirtiest air based on 2.5 particulate matter. Meanwhile leaving the heating and air conditioning on all the time (On) results in the cleanest air at the expense of using the most energy. The SmartAir plot shows that a system that turns on and off based on both temperature and air quality can result in a home with much cleaner air but without a much higher cost in energy.

The researchers, led by Patwari, purchased a series of off-the-shelf portable air pollution sensors and connected them wirelessly to Raspberry Pis, small and inexpensive computers for hobbyists. With specialized software developed by the engineers, the computers were programmed to automatically turn on the air conditioning system whenever the particulate matter in the air reached a certain point and turn off the system when the particulate matter dipped below a certain measurement.

For the study, 12 sensors were deployed in four homes in 2017. In each house, two of the sensors were inside rooms, and one was placed outside under a covered porch. Starting at midnight each night, each home would randomly operate the sensors under one of three conditions: “Normal,” in which the HVAC systems turned on and off normally based on temperature only; “Always On,” in which the air system operated continuously all day, and; “SmartAir,” in which the system turned on and off the HVAC fan based on the pollution measurement in the house as well as the thermostat’s temperature setting.

Based on five months of data, the study revealed that operating with the “SmartAir” setting in which it turned on and off based on temperature and air quality cleaned the air almost as well as if the HVAC fan was operating all day, but it used 58 percent less energy. Meanwhile, when the heating and cooling system operates normally without regards to the air quality, the air was 31 percent dirtier than with the “SmartAir” setting.

“For someone with asthma, an exacerbation can be triggered by poor air in the home, particularly for children,” Patwari says. “This kind of monitoring system could allow them to live more comfortably and with fewer asthma symptoms and fewer trips to the emergency room.”

Because of ordinary activities in the home such as cooking, vacuuming and running the clothes dryer, air quality inside a home can at certain times of the day be much worse than outside. Constant exposure to indoor air pollutants can lead to short-term health effects such as irritation of the eyes, nose, and throat, as well as headaches, dizziness, and fatigue, according to the United States Environmental Protection Agency. Long-term exposure could also lead to respiratory diseases, heart disease and cancer and could be fatal for some. Yet there are no known home or commercial HVAC systems that are controlled by air quality sensors.

Patwari’s study involves engineering in collaboration with other University of Utah scientists, including biomedical informatics and clinical asthma researchers. It was funded as part a larger National Institutes of Health program known as Pediatric Research using Integrated Sensor Monitoring Systems (PRISMS), launched in 2015 to develop sensor-based health monitoring systems for measuring environmental, physiological and behavioral factors in pediatric studies of asthma and other chronic diseases.

Research reported in this publication was funded by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under Award Number U54EB021973. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

As Utah residents know well, air quality can have a serious effect on our daily lives. Wildfires, inversions, dust, and pollution colliding with the complex geography of the Salt Lake region all contribute to the thick haze that can settle over the valley. However, the exact conditions and effects of these issues are not yet completely understood.

John Lin, professor of atmospheric sciences here at the University of Utah, will shine some light on these regional air quality problems in his lecture on Tuesday, September 11 in 210 ASB as part of the Global Change & Sustainability Center’s annual seminar series. Lin will lay out some of the complex conditions that affect air quality, and show just how interconnected they are to greenhouse gas emissions and climate change across the West.

He’ll explain how air quality can be indicative of many diverse conditions converging.

Of major concern in Lin’s research on Salt Lake City is dust blown off the Great Salt Lake. As the climate warms and water levels lower more frequently, dust is increasingly exposed to the air and carried into the atmosphere. Salt Lake City’s proximity to the lake leaves it particularly susceptible to the ill effects. This lake dust also effects snow, as it settles on the snowpack and causes it to melt faster.

Wildfires also play a big part in introducing particles to the atmosphere. Smoke from across the West can move hundreds of miles in the atmosphere to Utah. As climate change makes fires more frequent and intense, the relationship between global processes and regional air quality becomes more evident.

This relationship is visible in our daily lives.

“When we drive, the stuff that comes out of our tailpipes includes greenhouse gases but also NOx [Nitrogen Oxide] and PM2.5 which cause air quality problems,.” Lin said.

Often the source of local pollution is the source of emissions that drive climate change. Each contributes to a feedback loop that exacerbates their combined effect.

Lin’s research at the U has begun to uncover and understand the sources of these problems. Through two research groups, LAIR and U-ATAQ, Lin has used extensive data from a complex network of air quality monitoring systems throughout the region. The TRAX Air Quality monitoring system installed four years ago has been a major player in this network. The system has allowed Lin and his colleagues to closely monitor the valley’s air in its most densely-populated areas. Working together with city government, this research is directly informing new air quality initiatives in Salt Lake City. Collaborative work with the University of Utah Medical School is also applying this data to public health research.

The possibilities emerging from an understanding of how air quality and climate change intersect may have positive consequences outside of Utah.

“There’s a fair bit of interest from cities around the West who want to reduce emissions,” said Lin. “The cities are at the forefront, and hopefully the scientists can help in some way. What we hope to do is use our research to help assess if, with new measures in place, the reduction in emissions are actually happening.”

Come to Lin’s seminar, ” “The greenhouse gas-air quality nexus: experiences from the Western U.S.” at 4 p.m. in 210 ASB on Tuesday, September 11 to learn more about this cutting-edge research of the intersection of air quality and climate change, and how it affects us here in Salt Lake City and the West.

Living in Salt Lake City, we are no strangers to air pollution and its harmful effects. Breathing in toxic air can cause a range of health concerns including increased asthmatic symptoms, bronchitis, chronic obstructive pulmonary disease, and more.

It is no surprise that we often retreat into our homes to catch a breath of fresh air; however, sometimes our indoor air quality could be improved. Common indoor air pollutants include benzene, formaldehyde, trichloroethylene, xylene, and ammonia. There are certain plants that can combat these indoor air pollutants, according to a study done by NASA.

Here are five plants that can improve your indoor air quality:

FLORIST’S CHRYSANTHEMUM (Chrysanthemum morifolium)

Helps to rid the air of: Trichloroethylene, formaldehyde, benzene, xylene, and ammonia.

Care: Keep the plant in cooler temperatures and keep the soil moist at all times. Requires bright light.

Toxic? Chrysanthemum leaves are toxic so keep this in a safe spot away from any furry friends and youngsters.

Commuters who ride their bikes to work may be happier than their compatriots who drive solo. While cycling may not be feasible for all individuals, those who can partake may find relief from avoiding traffic congestion and breathing in the great outdoors. Biking is typically considered a fair-weather activity, but with a few additional layers and inexpensive bike additions, cyclists can continue to enjoy their commutes even as the temperatures fall. Don’t forget to log your bike trips in the Clean Air for U Challenge!